Initial assault (13–27 September)

On 13 September the elements of the 2nd Division were in position and ready to attack. The French Battalion, under Lt. Col. Ralph Monclar, had taken over the positions of the 38th Infantry Regiment on Hill 868, a little over 2 miles (3.2 km) east of Hill 931, and the 38th had become the division reserve with responsibility for surveillance of the Kansas line. The 9th Regiment was poised to advance on Hill 728 when the 23rd Regiment gained Hill 894. Direct support for the 23d Regiment would come from the 37th Field Artillery Battalion, under Lt. Col. Linton S. Boatright, and its 105mm howitzers, while the 503rd Field Artillery Battalion (155mm howitzer), 96th Field Artillery Battalion (155mm howitzer), 38th Field Artillery Battalion (105mm howitzer) and Battery C of the 780th Field Artillery Battalion (8-inch howitzer) provided general support. The 37th and 38th Field Artillery Battalions were located about 3 miles (4.8 km) southeast of Heartbreak Ridge. The 96th and 503rd were approximately 7 miles (11 km) south and 9 miles (14 km) southeast of the objective respectively, while the battery from the 780th was near Yach'on-ni, about 11 miles (18 km) south of Heartbreak.^[1]: 89

At 05:30 the artillery preparation began and for thirty minutes the guns pounded KPA positions on or near Heartbreak Ridge. Then Colonel Adams gave the signal to start the 23d's attack. The 3rd Battalion, under Lt. Col. Virgil E. Craven, led the way in a column of companies, followed by the 2nd Battalion, commanded by Lt. Col. Henry F. Daniels. As the assault troops moved north from Hill 702 up the Sat'ae-ri Valley to reach the east-west spur ridge that would serve as the approach to Heartbreak, the KPA spotted them. Heavy artillery and mortar fire from Heartbreak Ridge positions and from the heights around Sat'aeri town began to pour in on the men of the 23rd Regiment. Despite the growing number of casualties, Craven's forces pressed on, closely followed by Daniels' men. As the 3rd Battalion arrived at the east-west spur and headed up the hill to split the Heartbreak Ridge line, it ran into a hornet's nest. The KPA 1st Regiment, 6th Division manned a series of concealed, mutually supporting bunkers that covered the approach ridge with machine guns and small arms. Added to the artillery and mortar fire that the KPA observers were directing upon the two attack battalions, the automatic weapons and rifle fire forced the assault force to halt and dig in on the toe of the spur. The prospects for a swift penetration of the KPA lines vanished as night fell; the 23rd had come up against the KPA's main defenses and another Bloody Ridge experience loomed ahead.^[1]: 89

When reports of the 23rd's situation reached General de Shazo, he realized that he had underestimated the KPA's defensive capacity. Since the 9th Regiment, under Colonel Lynch, was already in position for its contemplated attack on Hill 728, on 14 September de Shazo directed Lynch to use his regiment against Hill 894 instead. A successful seizure of Hill 894 could relieve some of the pressure on the 23rd Regiment. The 2nd Battalion, 9th Regiment advanced from Yao'dong up the southwest shoulder of Hill 894 on 14 September, supported by tanks of Company B, 72nd Tank Battalion, the heavy mortar company, and a battalion of 155mm howitzers. By nightfall the 2nd Battalion had climbed to within 650 yards (590 m) of the crest of Hill 894 against light resistance. The attack continued on 15 September and by afternoon, the height was swept clear of the KPA. Up to this point the 2nd Battalion had had only eleven casualties, but the next two days cost the battalion over two hundred more as the KPA counterattacked fiercely and repeatedly in a vain effort to drive it off the crest. Possession of Hill 894 by the 9th Regiment failed, however, to relieve the pressure on the 23rd as it sought again to cut the ridge line between Hills 931 and 851. The KPA's firepower kept the assault forces pinned down on the lower slopes. On 16 September Colonel Adams ordered his 2nd and 3rd Battalions to shift from the column formation they had been using to attack abreast. Thus, while the 3rd Battalion renewed its drive due west, the 2nd Battalion swung to the southwest and approached Hill 931 along another spur. In the meantime, C Company of the 1st Battalion passed through the positions of the 9th Regiment on Hill 894 and tried to take Hill 931 from the south. The three-point attack made little headway against the heavy curtain of fire laid down by the KPA. Secure in their strongly fortified bunkers, the KPA defenders waited until the artillery and air support given to the 2nd Division assault forces was lifted and then returned to their firing positions. As the 23rd Regiment's soldiers climbed the last few yards toward the crest, the KPA opened up with their automatic weapons, rifles, and grenades. Since the KPA controlled the Mundung-ni Valley which offered defiladed and less steep access routes to Heartbreak Ridge, the problem of reinforcements and resupply was not difficult to resolve. In fact, General Hong Nim, commander of the KPA 6th Division, managed to send the fresh 13th Regiment in to replace the 1st Regiment on 16 September without any trouble. For the U.S. 2nd Division, the outlook was rather grim. The narrow Pia-ri Valley, southwest of Heartbreak, was jammed with vehicles and exposed to KPA artillery and mortar fire. Korean civilian porters frequently abandoned their loads along the trails and bolted for cover when the KPA got too close. To keep the front-line units supplied with food, water, ammunition, and equipment and to evacuate the casualties often required that American infantrymen double as carriers and litter bearers. The rugged terrain and the close KPA surveillance of the approaches to Heartbreak Ridge made their jobs very hazardous and time consuming, for it could take up to ten hours to bring down a litter case from the forward positions held by the 23d Regiment.^{[1]: 89–90}

The stalemate on the ridge led Colonel Lynch on 19 September to suggest a broadening of the attack to dissipate the KPA's concentrated resistance. He urged General de Shazo to let 1st Battalion, 9th Regiment move across the Mundung-ni Valley and seize Hills 867 and 1024 located about 3 miles (4.8 km) and 4 miles (6.4 km), respectively, southwest of Hill 894. If the KPA assumed that this attack marked the beginning of an envelopment of Heartbreak Ridge from the west, they might well divert men and guns to block the challenge, Lynch reasoned. But de Shazo rejected the proposal since General Clovis E. Byers, the X Corps commander, had earlier directed that Hill 931 be given first priority. When Maj. Gen. Robert N. Young, the new 2nd Division commander, arrived on 20 September, he decided that Lynch's plan was sound. He ordered Lynch to take Hills 867 and 1024 and the 9th Infantry commander scheduled the attack on Hill 1024 for 23 September; Hill 867 would be seized after Hill 1024 fell. In the meantime. Van Fleet told Byers that it would be desirable for X Corps to advance its western flank to bring the front line into phase with U.S. IX Corps'. Thus, Byers, on 22 September, directed the Republic of Korea Army (ROK) 7th Division to capture Hill 1142, located about 2,000 yards (1,800 m) northwest of Hill 1024. The double-barreled attack upon Hills 1024 and 1142 might well cause the North Koreans to take the threat seriously and lessen their capacity to resist on Heartbreak Ridge. The attacks by the 23rd Infantry against Heartbreak Ridge had continued on 21 and 22 September with little success. The 1st Battalion, under Maj. George H. Williams, Jr., had tried again to take Hill 931 from the south, while Daniels' 2nd Battalion came in from the north. Elements of the 1st Battalion briefly won their way to the crest on 23 September, but could not withstand the KPA's counterattack. An early morning assault from the east by a company from the KPA 3rd Regiment, 12th Division, produced a fierce fight that decimated the 1st Battalion. When his ammunition ran out, Williams had to pull back his men from Hill 931. Across the Mundung-ni Valley the diversionary attacks against Hills 1024 and 1142 by the 9th Regiment and the ROK 7th Division made good progress. On 25 September the 1st Battalion, 9th Infantry, cleared the crest of Hill 1024 and the ROK 7th Division won Hill 1142 the following day. Recognizing the threat to neighboring Hill 867, a key terrain feature dominating the valley to the north, the North Koreans quickly shifted the 3rd Regiment, 6th Division, from Heartbreak Ridge to defend the hill. The North Korean deployment, however, did not help the embattled 23rd Regiment to capture Hill 931. Although the French Battalion replaced the 2nd Battalion and tried to advance south along the ridge line while the 1st Battalion sought to press north toward the crest of 931, the KPA 15th Regiment fought them off on 26 September. The 23rd's regimental tanks were able to move far enough north in the Sat'ae-ri Valley to send direct fire against some of the KPA bunkers covering the eastern approaches to Heartbreak, but could not destroy the heavy mortars and machine guns that halted the 2nd Division attack.^{[1]: 90–1}

After almost two weeks of futile pounding at the KPA defenses on Heartbreak, Colonel Adams told General Young on 26 September that it was "suicide" to continue adhering to the original plan. His own 23rd Regiment had already taken over 950 casualties and the division total for the period was over 1,670. As Colonel Lynch had the week before, Adams favored broadening the attack and dispersing the KPA's capacity to resist on Heartbreak. He felt that if the KPA forces in the vicinity of Heartbreak were engaged and unable to spare reinforcements or replacements for the KPA 15th Regiment, the 23rd could wear the regiment down and win the ridge. By 27 September Young and the Corps commander, General Byers, had come to agree with Adams and further assaults by the 23rd on Heartbreak were called off. Analyzing the initial attempts of 2nd Division to take Heartbreak, Young later characterized them as a "fiasco" because of the piecemeal commitment of units and the failure to organize fire support teams. The KPA mortars were especially effective, he pointed out, causing about 85 percent of the division's casualties up to this point.^{[1]: 91–2}

Renewed assault (4–15 October)

Operation Touchdown

On 4 October forty-nine fighter-bombers worked over the divisional sector and Task Force Sturman raided the Sat'ae-ri Valley. The other units of the 2d underwent final rehearsals for the attack scheduled for 21:00 the next night. Fire support teams usually consisting of a combination of mortars, machine guns, rifles, and automatic weapons that could be called upon by the attacking infantry whenever the need arose were set up and given dry runs. The additional firepower would be extremely valuable against KPA bunkers and strongpoints. In the late afternoon of 5 October, the artillery preparation opened up as the division's artillery battalions began to pummel the defending KPA units facing the 9th and 38th Regiments in the Mundung-ni Valley area. Deployed from west to east the KPA 3rd Regiment, 12th Division, occupied Hill 867; the 1st Regiment, 6th Division, was spread from Hill 636 northwest to Hill 974; and the 15th Regiment, 6th Division, was dug in on Hill 931. As a result of the constant pressure exerted by the 2nd Division on these units during September and early October, none of them had a strength that reached a thousand men. The KPA 12th and 6th Divisions were both far understrength by the eve of Touchdown.^{[1]: 93–4}

Air strikes by United States Marine Corps F4U Corsairs sent Napalm, rockets, and machine gun bullets into the KPA lines before the attack jumped off that evening. On the west the 3rd Battalion, 9th Infantry, pressed on toward Hill 867 and by 7 October had won the crest, meeting only light resistance. The battalion then swung northwest toward Hill 960 while the 1st Battalion mounted an attack north against Hill 666. Both hills fell on 8 October. Then the 9th pushed on to Hill 1005 northwest of Hill 666 and after a bayonet assault took possession on 10 October. On the following day the ROK 8th Division gained Hill 1050 and the Kim Il Sung range to the west of the 9th Regiment. The 38th Regiment, in the meantime, had also made excellent progress, on 4 October they discovered that the KPA had abandoned Hill 485, 1 mile (1.6 km) south of Hill 728. By noon on 6 October the 1st Battalion had advanced from Hill 485 and seized Hill 728 against only light opposition. The 2nd Battalion deployed up the Mundung-ni Valley and attacked Hill 636 which fell on 8 October. Possession of these two hills furnished cover for Colonel Love's engineers, who could now complete the tank trail for the 72nd Tank Battalion's advance. The 72nd, commanded by Lt. Col. John O. Woods, was attached to the 38th on 7 October and the regiment was given three new objectives: Hill 605, 2,000 yards (1,800 m) north of Hill 636; the Hill 905-Hill 974 ridge which extended northwest from Hill 636 toward Hill 1220 on the Kim Il Sung range; and Hill 841, 1,000 yards (910 m) north of Hill 974.^[1]: 94

Up on Heartbreak Ridge the 23rd Regiment was also able to report encouraging news. Colonel Adams' battle plan had directed Major Williams' 1st Battalion to exert diversionary pressure north against Hill 851, while the French Battalion feinted south toward Hill 931. Daniels' 2nd Battalion would hit Hill 931 from the south with Craven's 3rd Battalion as reserve behind Daniels. Under cover of night and the distractions provided by the rest of the division, Daniels' troops moved out. KPA fire came in quickly upon the battalion, but the North Koreans could not concentrate all their attention upon this assault. With the 3rd Battalion in support, Daniels' force slowly approached Hill 931. To preserve the element of surprise, there had been no artillery preparation. The 37th Field Artillery Battalion opened up on all known KPA mortar positions as the attack got under way. The effectiveness of the counter-mortar fire helped the 23rd infantrymen as they closed with the KPA after only light losses. Flame throwers, grenades, and small arms rooted the KPA from the formidable bunkers that had blocked the 23rd's advance for so many weeks. By 03:00 the 2nd and 3rd Battalions had won the southern half of Hill 931. The expected KPA counterattack came and was repulsed. With the coming of daylight, the advance was renewed. The French Battalion moved in from the north and the 2nd and 3rd Battalions pressed on to meet it; before noon Hill 931 finally belonged to the 23rd Infantry. Craven's 3rd Battalion then pushed on to join the 1st Battalion in its assault against the last objective on Heartbreak Ridge, Hill 851.^{[1]: 94–5}

In the Sat'ae-ri Valley, Task Force Sturman's tanks sustained their daylight raids and continued to blast away at the bunkers on the eastern slopes of Hill 851. On the west, in the Mundung-ni Valley, Woods's 72nd Tank Battalion awaited the go-ahead signal from Love's engineers. On 10 October the engineers finished their task and the 72nd's Shermans, accompanied by Company L, 38th Infantry, and an engineer platoon, began to rumble north up the valley. By a fortunate coincidence the KPA was caught in the middle of relieving the rapidly disintegrating elements of the KPA V Corps in the Heartbreak Ridge-Mundung-ni sector. Advance elements of the People's Volunteer Army (PVA) 204th Division, 68th Army, were in the process of taking over positions already vacated by the KPA. The tank thrust coupled with the general forward movement of the rest of the 2nd Division found the PVA still in the open en route to their new positions. Woods's tankers raced to the town of Mundung-ni and beyond, taking losses on the way, but inflicting heavy losses upon the PVA troops and cutting off the supply and replacement routes up the western slopes of Heartbreak Ridge. At intervals of about 100 yards (91 m) the tanks, operating without infantry in the northern reaches of the valley, were able to cover each other and fire at targets of opportunity. They disrupted the PVA relief completely and made the task of the infantry much lighter in the days that followed. It was apparent that the KPA/PVA had thought that tanks could not be used in Mundung-ni Valley and the feat of Love's engineers in opening a road had taken them by surprise. The battle, however, was not quite over. The 3rd Battalion, 38th Infantry, took advantage of the tank advance to seize Hill 605, but the 2nd Battalion's attempts to capture Hill 905 were blunted on 10 October. The next day the 2nd Battalion overcame PVA/KPA opposition and the 1st Battalion took Hill 900. On 12 October the 1st Battalion pushed on toward the Kim Il Sung range and captured Hill 974. The final objective of the 38th, Hill 1220, fell on 15 October.^[1]: 95

On Heartbreak Ridge the KPA 23rd Regiment, 13th Division, defended Hill 851, backed by its sister regiments, the 21st and 19th. The 21st was to the immediate rear and the 19th defended the Sat'ae-ri Valley. On 10 October, Colonel Daniels' 2nd Battalion had swung down from Heartbreak Ridge and taken possession of Hill 520, a little over 1 mile (1.6 km) south of the town of Mundung-ni. Hill 520 was the end of an east-west ridge spur leading to Hill 851. During the next two days, the 1st and French Battalions inched north toward the objective, bunker by bunker, taking few prisoners in the bitter fighting. The KPA/PVA on Hill 951 had to be killed or wounded before they would cease resistance. Colonel Craven's 3rd Battalion shifted to the spur between Hills 520 and 851 to apply pressure from the west. Finally at daybreak on 13 October, Monclar's French troops stormed the peak and after thirty days of hard combat, Heartbreak Ridge was in the possession of the 23rd Infantry.^{[1]: 95–6}